1. Field of the Invention
The present invention relates to keyboard technology and more particularly, to a keyboard backlight module with improved light guide structure, which has high-refractive index scatter points mounted in the top surface and or bottom surface of a light guide layer of a backlight device between a reflective layer and a light shielding layer for refracting light to enhance the illumination brightness.
2. Description of the Related Art
With fast development of the modern technology, many different kinds of works, including word processing, photos and graphics editing and etc. are implemented through a computer. A computer can also be linked to the Internet for information search, online shopping, online meeting, data download, playing online video games, and many other applications. When operating a computer, different peripheral apparatuses may be used for different application purposes. In addition to the host and monitor, a computer system also needs to use a keyboard and a mouse as requisite tools. A computer keyboard uses a set of key switches for allowing the user to input control signals, text, numerals and other data into the host for processing.
Further, a computer keyboard may equipped with a backlight module for emitting light to each key switch so that the user can clearly identify the location of the key that is duly pressed. FIG. 6 illustrates a keyboard backlight module according to the prior art. According to this design, the backlight module A comprises a light guide panel A1, a reflective panel A2 located at the bottom side of the light guide panel A1, a light shielding panel A4 located at the top side of the light guide panel A1, a light source A3 mounted in the light guide panel A1 between the reflective panel A2 and the light shielding panel A4 for emitting light into the light guide panel A1, and a plurality of reflecting points A11 mounted on the bottom surface of the light guide panel A1. During operation of the backlight module A, light rays S emitted by the light source A3 fall upon the light guide panel A1 and are then refracted by the light guide panel A1 onto the reflecting points A11, and then reflected by the reflecting points A11 toward the light shielding panel A4 so that the reflected light rays S1 can go to the outside through holes in the light shielding panel A4 to illuminate the respective key switches. However, when light rays S are reflected by the reflecting points A11 toward the top side of the light guide panel A1, a part of the reflected light rays S2, S3, S4 will be reflected backwards by the top wall of the light guide panel A1, resulting in weakened illumination brightness. Further, the energy of the reflected light rays S2, S3, S4 can be absorbed by the light guide panel A1, causing light attenuation and energy loss problems and insufficient illumination. Further, because the reflecting points A11 are mounted on the bottom surface of the light guide panel A1, the reflected light rays S2, S3, S4 must travel along a long reflection path before reaching the light shielding panel A4, and thus, the light rays can be diffused in the border area or absorbed and attenuated by the light guide panel A1, affecting the lighting performance of the backlight module A. An improvement is necessary.
Therefore, it is desirable to provide a keyboard backlight module, which shortens the reflection path, prevents loss of light energy, and greatly enhances the illumination brightness.